Long telomeres, the endcaps on DNA, not the fountain of youth once thought, and scientists may now know why

In a study of 17 people from five families, Johns Hopkins Medicine researchers say they found that ultra-lengthy DNA endcaps called telomeres fail to provide the longevity presumed for such people. Instead, people with long telomeres tend to develop a range of benign and cancerous tumors, as well as the age-related blood condition clonal hematopoiesis.